Synthesis of 2-(Bis(Phosphonomethyl)Amino)Ethane-1-sulfonic Acid Intercalated ZnAl Layered Double Hydroxide as an Efficient Adsorbent for Hg ²⁺ Ions and Antimicrobial Agent

Mercury is a pollutant of concern due to its negative influence on the environment and human health. Hydrotalcites, also known as layered double hydroxides, have attracted tremendous attention over the last few years in several fields such as healthcare and environmental remediation. Herein, a novel hybrid ZnAlLDH was synthesized to test its effect on mercury adsorption capacity. ZnAl-CO3/LDH synthesized using the co-precipitation method is grafted with a new phosphonic acid named2-(bis(phosphonomethyl)amino)ethane-1-sulfonic acid synthesized in our laboratory. Materials were characterized using textural, structural and morphological analysis. Mercury removal is measured by adsorption tests under relevant conditions. Parameters affecting the extraction process such as stirring speed, adsorbent dose, Hg<sup>2+</sup> concentration, pH, ionic strength and temperature were fully studied and discussed. In effect, LDH intercalation with phosphonic acid and the optimization of mercury adsorption conditions improved the adsorption capacity of the prepared material by ca. 40%.87% of Hg<sup>2+</sup> was successfully removed from aqueous solution. The hybrid LDH was also investigated in antibacterial and antifungal activities against Gram-negative (Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (A22), Pseudomonas aeruginosa (ATCC27853) and Acinetobacter baumannii (ATCC17978)), Gram-positive (Bacillus (ATCC11778), Staphylococcus aureus (ATCC25922), Staphylococcus aureus (ATCC43300) and Staphylococcus aureus (ATCC25923)) bacteria and Candida albicans (ATCC26790) fungus.